A system for assuring quality-of service for Data Network Telephone calls, such as Internet Protocol Network Telephony calls has software for monitoring established DNT calls for adequate bandwidth. A detection pulse generating part generates a detection pulse to replace the multi-pulse series; and a detection power control part controls the power of the detection pulse to be smaller than the power of the multi-pulse series. \u201cSoft\u201d biopolymers tend to be more flexible and pliable and typically have a glass transition temperature less than about 0\xb0 C. The resin composition is improved in durability without deteriorating the excellent properties of the resin, such as being colorless and transparent.